Deflection of Nested Cold-Formed Steel Z-Section Beams
Publication: Journal of Structural Engineering
Volume 128, Issue 11
Abstract
Stiffened Z-section beam purlins were tested to evaluate the deflection behavior of lap joints under combined bending and shear. The tested beams had a span length of 243.84 cm (8 ft), nominal web depths of 20.32 cm (8 in.) and 24.13 cm (9.5 in.), and a metal thickness ranging from 1.542 mm (0.060 in.) to 2.565 mm (0.101 in.). The corresponding web depth-to-thickness ratio ranged from 79 to 131. The experimental program included testing a single section beam of each Z section and lapped beams with lap-to-span ratio ranging from 0.25 to 1.0. The test results indicated that the lapping process enhanced the ultimate load capacity and stiffness of the beams. This enhancement was more pronounced for beams with lap-to-span ratios less than or equal to 0.5. For higher ratios, little or no change in the results was noted. The failure mechanism was governed by bending stresses and was caused by buckling of the compression flanges at stress levels close to the yield stress of the parent steel. A relative stiffness behavior approach was used to analyze the results. This approach compares the deflection behavior of lapped beams with that of a single section beam having the same span length and the same Z section. Based on this analysis, semiempirical equations were obtained to predict the deflection of lapped beams. Theoretical deflection equations were also derived and the results based on these equations were compared with the experimental results. It was concluded based on this comparison that the proposed correlation was adequate for predicting the deflection in the lap joint zone of nested Z beams.
Get full access to this article
View all available purchase options and get full access to this article.
References
American Iron and Steel Institute (AISI). (1990). Specification for the cold-formed steel structural members, New York.
Ghosn, A. A., and Sinno, R. R., (1995), “Governing stresses in Z purlin lap joints.” J. Struct. Eng., 121(12), 1735–1741.
Ghosn, A. A., and Sinno, R. R.(1996), “Load capacity of nested, laterally braced, cold-formed steel Z section beams.” Ground Water, 122(8), 968–971.
Timoshenko, S. P., and Gere, J. M. (1961). Theory of elastic stability, McGraw-Hill, New York.
Information & Authors
Information
Published In
Copyright
Copyright © 2002 American Society of Civil Engineers.
History
Received: Sep 19, 2000
Accepted: Mar 12, 2002
Published online: Oct 15, 2002
Published in print: Nov 2002
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.